1. Field of the Invention
The invention relates in general to a display apparatus, and more particularly to a double-faced display apparatus.
2. Description of the Related Art
Compared to other flat-panel-display technologies, the organic electroluminescence device (OELD) has many advantages over today's liquid crystal display (LCD) or plasma display due to its excellent features, such as self-illumination, high brightness, large view-angles, high contrast, low power consumption, high-speed response, large range of operational temperature, and simple manufacturing process. In general, the conventional OELD employs a multiple-layer structure, and an organic light-emitting layer used for light emission is disposed between an anode layer and a cathode layer. A hole injection layer (HIL) and a hole transporting layer (HTL) are formed between the organic light-emitting layer and the anode layer; an electron transporting layer (ETL) is formed between the organic light-emitting layer and the cathode layer. Such a multi-layer structure is good for electrons injected from the cathode to flow toward the anode. The organic light-emitting layer can be divided into two classes in terms of the materials. One class is a small-molecular light-emitting diode primarily made of dyes or colors, which is called an organic light-emitting diode (OLED) or OELD. The other class is primarily made of polymer materials, which is called a polymer light-emitting diode (PLED) or light-emitting polymer device (LEPD).
The common method for manufacturing a double-faced display apparatus is to combine two single-faced display apparatuses. Referring to FIG. 1, a cross-sectional diagram of a conventional double-faced display apparatus is shown. A double-faced display apparatus 10 includes two single-faced display apparatuses 11, and each single-faced display apparatus 11 includes a glass substrate 12, a back cover 13, an OELD 15 and a drying agent 16. The back cover 13 is attached on the glass substrate 12 with its opening faced to the glass substrate 12 to form a sealed space. The OELD 15 is disposed in the sealed space 14 and located on the glass substrate 12. The drying agent 16 is disposed in the sealed space 14 and partially covers the OELD 15.
In the fabrication of the double-faced display apparatus 10, the two single-faced display apparatuses 11 are fabricated individually and then combined back to back. That is, the back covers 13 of the upper and lower single-faced display apparatuses 11 are face-to-face touched and attached to each other to fabricate the above-mentioned double-faced display apparatus 10.
However, the double-faced display apparatus 10 formed by the fabrication of the two single-faced display apparatuses 11 has larger thickness and weight, and thus higher cost.
Besides, the drying agent 16 absorbing water would lead to the increase of weight and volume of the display apparatus 11, and the deformed drying agent 16 with an increasing weight will press the OELD 15 to break, thereby greatly influencing the quality of the double-faced display apparatus 10.